446 



NA TURE 



\Oct, I, 1874 



rendered capable of the greatest possible amount of 

 extension. 



On the upper surface of the skull, clamping the lateral 

 occipital region and projecting backwards for fully half 

 its length beyond the latter, is the flat sabre-likc squa- 

 mosal (Fig. 21, Sq), articulated to the hinder end of 

 which, and thus carried completely away from the audi- 

 tory region, is the quadrate, a stout bone passing 

 obliquely downwards and outwards, and giving attach- 

 ment by a rounded pulley-like surface to the mandible. 

 On the inner edge of the quadrate, and partly coalesced 

 with it, is a small nodular ossification representing 

 the stylo-hyal (Figs. 21 and 22, St.lly). The palatines 

 and pterygoids are well developed and bear large recurved 

 teeth ; the latter extend backwards to the quadrate, to 

 which they are united by ligaments just above its articular 

 surface. The maxilla; arc large strong bones lying parallel 

 with the palatines and the front half of the pterygoids, 

 and forming an outer dentigerous arch. Between the 

 hinder end of the maxilla and the centre of the pterygoid 

 rims a stout bone, the os transversum, found in this dis- 

 tinct form in all Ophidia, as well as in Lacertilia and 

 Crocodilia, and occurring as a rudiment in some birds. 



The two rami of the mandible are united at the sym- 

 physis by elastic fibrous tissue only, and each consists of 

 six separate ossifications more or less fased together in 

 the adult. These are the articular (Art) coming into 

 relation with the quadrate, the angular (Ang) and supra- 

 angular (S. Ang) applied, one above and one below, to 

 the outer surface of the articular, the dentary (D) bear- 

 ing the teeth, and the splenial (Spl) and coronary (Cor) 

 appearing only on the inner surface. 



The columella or auditory ossicle is extremely small in 

 the common snake (Fig. 23, Col), and consists of a plug 

 of bone fitting into the fenestra ovalis by a rounded disc- 

 like end, the stapes, and of an extremely short rod 

 anchylosed with and projecting backwards from the 

 disc, which is all that represents the stapedial bones of 

 the frog. In many of the larger serpents, both venomous 

 and harmless, the columella is a rod of very considerable 

 length, tipped at its end, in some cases, by an expanded 

 cartilaginous flap, the homologue of the extra-stapedial. 



The earlier stages in the development of the snake's 

 skull have been well worked out by Kathke (" Entwicke- 

 lungsgeschichte dcr Natter "). Abstracts of his views will 

 be found in Prof. Huxley's Croonian Lecture (Proc. Roy. 

 Soc, 1858^, and in the " Elements of Comparative Ana- 

 tomy " ot the same author (p. 237). The earliest stage 

 described by the lecturer corresponds with Rathke's 

 third period, when chondrification is already thoroughly 

 established, and the slender trabecuhr; have united 

 behind with the investing mass, and in fiont with each 

 other (see Fig. 24). The notochord (Ch) reaches only to 

 the middle of the broad investing mass (l.M), a large 

 membranous space, the "posterior basi-cranial fontanelle " 

 of Rathke (p.b.c.f) being between its anterior pointed 

 end and the " anterior basi-cranial fontanelle," or pitui- 

 tary space. A large occipital ring is already formed by 

 the growing up of the iu\esting mass around and above 

 the neural canal, and articulating with its edges are the 

 sub-triangular auditory capsules, on which the elevations 

 caused by the semicircular canals (a.s.c, p.s.c, h.s.c) are 

 particularly well marked. The trabecuke diverge strongly 

 m the pituitary region, in front of it run almost parallel, 

 having between ttiem the tissue from which the para- 

 sphenoid is afterwards formed, and eventually unite and 

 expand into the large reniform roofs of the nasal sacs 

 (Na). The alisphenoids (Al.s) are already chondriried, 

 but the orbito-sphenoids (O.s) are backward in develop- 

 ment, being mere patches of indifferent tissue in front of 

 the exit of the optic nerve (11). The mandibular arch is 

 completely divided into a short quadrate and a long 

 Meckel's cartilage. The hyoid arch is cartilaginous only in 

 its upper part, and its ape.K is already fused with the stapes. 



In the second stage all the bones of the adult have 

 appeared with the exception of the alisphenoid, orbito- 

 sphenoid, columella, stylo-hyal, and otic bones. The basi- 

 occipital arises in the same manner as the urostyle of a 

 frog or osseous fish,* as a bony deposit in the sheath of the 

 notochord, affecting subsequently the surrounding carti- 

 lage ; the basi-sphenoid makes its appearance as a pair of 

 ossific centres, one on each side of the apices of the tra- 

 becula;, where they join the investing mass. The parietals 

 and frontals are quite normal in their development, arising 

 as symmetrical ossifications in the supero-lateral region of 

 the membranous cranium, and only acquiring their 

 anomalous adult character by downward extension 

 towards the base of the skull at a later period. In this 

 stage a segment has separated from the hyoid arch and 

 attached itself to the inner border of the quadrate : this is 

 the stylo-hyal, the remainder of the arch now constituting 

 the columella. 



In the third stage, consisting of snakes at the point of 

 hatching, all the ossifications have appeared, with the 

 exception of the orbito-sphenoid, which is unusually late 

 and uncertain in its development. Besides the three 

 chief otic centres, which are perfectly distinct from the 

 occipital regions, a plate of bone is to be seen in this 

 stage within the lower edge of the squamosal : this answers 

 to the ectosteal plate of the pterotic, so largely developed 

 in osseous fishes. Lastly, the jaws have acquired their 

 adult character by the loosening of the quadrate from the 

 auditory capsule and its retrogression to its adult posi- 

 tion, articulating with the hinder end of the backward- 

 turned squamosal. 



NOTES 



A MOVEMENT which has been for some time on foot for 

 establishing in London a School of Medicine for Women is now 

 so far matured that the school will be opened for the winter 

 term on Oct. 12, in commodious premises, 30, Menrietta Street, 

 Brunswick .Square. The full stall of lecturers has not yet been 

 appointed, but among those who have already consented to take 

 part in the instruction are Dr. King Chambers in the practice of 

 Medicine, Mr. Berkeley IliU in Surgery, Mr. A. T. Norton in 

 Anatomy, Dr. Sturges m Materia Medica, Mrs. Garrett Ander- 

 son in Midwifery, Mr. Critchett in Ophthalmic Surgery, Dr. 

 Clieadle in Pathology, Mr. Heaton in Chemistry, and Mr. A. W. 

 Bennett in Bocany. The following gentlemen have, in addition, 

 consented to serve on the Council : — Dr. Billing, Dr. Buchanan, 

 Mr. Ernest Hart, Prof. Huxley, Dr. Ilughlings Jackson, Dr. 

 Murie, Dr. F. Payne, Dr. \V. S. Playfair, and Dr. Burdon- 

 Sanderson, as well as Dr. Elizabeth Blackwell. A fair number 

 of students are already enrolled. It is intended to build a 

 detached dissecting-room in the garden attached to the house. 



Dr. William Rutherford has been appointed to the 

 Professorship of Physiology at the University of Edinburgh, 

 vacated by the resignation of Dr. J. Hughes Bennett. Dr. 

 Rutherford, in accepting his new appointment, vacates the 

 Professorship of physiology at King's College, London, the 

 Assistant-Pliysicianship at King's College Hospital, .and the 

 FuUerian Professorship at the Royal Institution. The duties of 

 the first of these will most probably be undertaken, during the 

 coming session at least, by Dr. David Ferricr. 



Dr. AdolI'- Ber.nii.vrd Meyer, the recent exploier of New 

 Guinea, has, been appointed director of the Zoological Museum 

 at Dresden, in succession to Dr. Reicheubach, who has retired. 



* III thcsi: types n vari.iblc number of vertebra; at the termination of the 

 column undergo a process of absorption, .ind a single ossification appearing 

 111 thcshc-tth ol the notochord constitutes the urostyle or coccyx. Id the 

 hc.id a similar process lakes pLice at the anterior end of the notochord, where 

 a number of vertebra: may be considered to have been suppressed, lorming 

 what may be teriiie J a ' ' cephalostyle " : the bony deposit spreading from thU 

 into the investing mass, gives rise to the basi-occipital. 



